Mechanical-feeding furnace



/W AX G. GRGNDAL.

MECHANICAL FEEDING FURNACE. APPLICATION FILED I\1AY2( ),1918.

1,360,210. Patented Nov. 23, 1920.

2 SHEETS-SHEET I.

I r 1 7 a Ill I 7 II II I fllllllfillillim l INVENTOR 4 G as THF' GRIVBRL G. GRDNDAL.

MECHANICAL FEEDING FURNACE.

APPLICATION FILED MAY 20-,191 a.

2 O Patented Nov. 23, 1920.

2 SHEETS-SHEET 2.

' IN EN OR GUSTAF GRfiNDAL, F DJURSI-IOLM, SWEDEN.

MECHANICAL-FEEDING ACE.

Specification of Letters Patent.

Patented Nov. 23, 1920.

Application filed May 20, 1918. Serial No. 235,571.

To all win mi it may concern:

Be it known that l, Gusrnr GRiiNoAL, a subject of the King of'tlweden, and resident of Djursholm, Sweden, have invented certain new and useful improvements in Mechanical-Feeding Furnaces, of which the following is a specification.

F or roasting sulfurous ores mechanical furnaces of the Macdougall type are almost exclusively used; they have been found to be highly suitable for sulfur pyrites. but when a sulfurous ore is to be treated which requires a relatively h h temperature for its desulfurization ti can scarcely be cm pl eyed, as the members which cause the ore to be fed through the furnace are made of metal and consequentlyinappropriate even though they are continually cooled.

furnace for roasting such ores as require a high roasting temperature has lately been relatively much employed; this furnace is invented by de. Spirlet; besides its good qualities in several respects it has however some inconveniences as a rather large consiunptiou of fuel, small output and a cornplicated construction.

By my present invention a furnace is obtained which has all the good qualities of the constructions of uf'naces mentioned eve. but at tie same time does not suffer from their inconveniences and defects.

The invention misists therein that in the arch of the for see there are fixed certain feeding members of a convenient form by means of which the material placed on the hearth bel w is pushed forward by effecting a relative movement of the arch or roof and the hearth. as further described in. connection win the different forms shown on the annexed drawings. a

Figure 1 is a longitudinal section and Fig. :2 is a transverse section of a furnace according to the invention. Fig. 3 shows a detail of the furnace arch. Fig. l is a transverse section of a portion. of the furnace arch of modified form. 5 is a transverse section through some of the feeding members in this modification. Fig. 6 shows a side view and Fig. 7 a transverse section of the furnace according to the said modification in which the roof is movable. 8 and 9sl1ow, in a longitudinal and transverse section respectively, a form of furnace having a movable hearth.

In the form shown in Figs. 1 to 8 A represents the hearth on which the material to be treated enters through the inlet opening B provided with x b a feeding device (not shown). (1 ma fire pl ace communicating with chain (eels D, D, D, by means of which the hearth. A. is heated. The combustion prmlucts escape through the chimney flue E.

The material fed on to the hearth A through the opening B is continually moved in the direction of the fireplace by the movable roof (i provided with rabbles F, F, F; the movement bein im darted to the roof by the mechanical device I which first moves the roof forward in a horizontal direction, then lifts it to an extent corresponding to the thickness of the material and in this elevated position moves it back in a horizontal direction as far as it was previously moved forward, after which it again lowers the roof, and to this end the arch G is connected by forks a and the link I) with the lever c which at its other end carries a counterweight d. The lever c is mounted on the shaft e journaled in bearings (not shown) supported on beams L. To the lever c is rigidly secured the upper end of a bar f, the lowerend of which is connected by the rod 9 and its associated link 9 to an eccentric la. mounted on a driving shaft Z which is rotated from any suitable source of power. The shaft-Z also has a crank arm or to which is connected the link m, which in turn is jointed to the rod m secured to the arches m of the roof. The rotation of the ecccn-- tric 72, imparts an up and down movement to the roof, while the crank 17?. imparts a back and forth motion to the roof. The rabbles .F, F, Fmay have the shape of plows and be arranged? in such a manner as to stir the materialas well as to carry it forward. The finished material leaves the furnace through the outlet opening I and is collected in the chamber K, from which it can be removed by a conveying screw (not shown) or through the. gate L.

The air necessary for roasting is admitted through the channel M. T e gases generated in the furnace chamber N escape throughthe channel 0.

The arch G is provided all around with a screen P of metal plate dipping into a trough R filled with sand or water by which. the outer air is prevented from entering into the furnace chamber.

If the furnace is to be used for the dry- 'distillation of comminuted material either so much air may be admitted into the fur nace chamber that the heat generated by a partial combustion of the material creates the temperature necessary for the distillation orthe furnace may be heated by firing 1O after being carried forward for instance delivery end of the furnace and simultaneously said air is highly heated.

The fact that the furnace chamber can be completely shut off from the outer air makes possible to introduce, if necessary for the reaction, another gas than air such as carbon oXid or nitrogen.

' The form just described has certain advantages; thus for'instance by lifting the roof the hearth is instantaneously accessible 7 to inspection which is of great importance in roasting such ores as are apt to form solid crusts on the hearth. The combined movement of the roof forward, upward,

rearward and downward, however, is rather complicated and I therefore havesimplified the construction by giving to the feeding members" such a shape that the movement of the roof and hearth relatively to each other need take place in one plane only. In this case a reciprocating movement is imparted to the roof or to the hearth. At the forward movement of the roof the ore 'mineral is then pushed forward, at the rearward movement, however, it is pushed toward thesides; if the hearth is movable the movements are inverted. he construction of the feeding members is seen from Figs. 4 and 5.

As represented the feeding members (see. Fig. 5) consists of prismatical rabb angularin cross'section, having their faced away from the outlet. The rabhles are rigidly fixed to the roof of the furnace. By means of the transverse faces 6, i), b of the rabbles the material is pushed forward a certain distance on the movement of the roof or the hearth in one direction. At the return movement the material is pushed by the oblique sides 8, s more or less (depending on the size. of the angle at the apex) laterally in the path of the transverse sides of adjacent rabbles, which again during the next movementof the roof (or hearth) push the material toward the outlet and so forth. "By this rabble device the material not only iscarried forward but also stirred and turned around, which as well known is of very great importance for an effective roastmg. Figs. Grand 7 representan arrangement of the furnace in which the roof is movable; the roof 0 is carried on the rollers d, d, d and a reciprocating movement is imparted to the roof by a suitable mechanism (not shown).

In Figs. 8 and 9 a furnace device is shown in which the roof 0 is stationary, while the hearth c, which rests on the wheels f, f, f, is movable, and a reciprocating movement is imparted to it by means of a suitable mechanism (not shown).

it is evident that the forms according to the invention described above may be modified without departing from the spirit of the invention.

I claim 1. A furnace comprising a hearth and a roof therefor, feeding members carried by the roof and projecting toward the hearth. and means for securing a relative back and forth motion between said roof and hearth to impart a feed motion to the material on the hearth, together with means for sealing against atmosphere the chamber formed between the hearth and roof.

2. A. furnace comprising a hearth and a roof therefor, feeding members carried by the roof and projecting toward the hearth. means for securing a relative back and forth motion between said roof and hearth to impart a feed motion to the material on the hearth, and means for sealing against atmosphere the chamber formed between the hearth and roof, together with means arranged beneath the l arth for heating the latter.

3. A furnace comprising a hearth and :1 roof therefor, feeding members carried bv the roof and projecting toward the hearth. and means for securing a relative back and forth motion between said roof and hearth to impart a feed motion to the material on the hearth, together with means for sealing a ainst atmosphere the chamber formed be tween the hearth and roof, said sealing means comprising ins carried by one of said members, and troughs associated with the other member and into which the ins dip.

f. A furnace comprising a hearth and a roof therefor, feeding members carried by the roof and projecting toward the hearth. and means for securing a relative back and forth motion between said roof and hearth to impart a feed motion to the material on the hearth, together with means for sealingagainst atmosphere the chamber formed between the hearth and roof. said feed members being shaped to effecta raveling action on the material on the hearth as well as to ac vance said material thereon.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses.

G. GRONDAL.

Witnesses .E. HoLMnLAn,

L. LENNARTSSON.

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